The 60 GHz band is an unlicensed band which features a large amount of bandwidth and a large worldwide overlap. The large bandwidth means that a very high volume of information can be transmitted wirelessly. As a result, multiple applications, that require transmission of a large amount of data, can be developed to allow wireless communication around the 60 GHz band. Examples for such applications include, but are not limited to, wireless high definition TV (HDTV), wireless docking stations, wireless Gigabit Ethernet, and many others.
In order to facilitate such applications there is a need to develop integrated circuits (ICs), such as amplifiers, mixers, radio frequency (RF) analog circuits, and active antennas that operate in the 60 GHz frequency range. An RF system typically comprises active and passive modules. The active modules (e.g., a phase-array antenna) require, control and power signals for their operation, which are not required by passive modules (e.g., filters). The various modules are fabricated and packaged as RFICs that can be assembled on a printed circuit board (PCB). The size of the RFIC package may range from several to a few hundred square millimeters.
In the market of consumer electronics, the design of electronic devices, and thus RF modules integrated therein, should meet the constraints of minimum cost, size, and weight. The design of the RF modules should also take into consideration the current assembly of electronic devices, and particularly handheld devices, such as laptop and tablet computers in order to enable efficient transmission and reception of millimeter wave signals.
A schematic diagram illustrating the assembly of a laptop computer 100 that includes an RF system 110 for transmission and reception of millimeter wave signals is shown in FIG. 1. The form factor of the RF system 110 is spread between the base 102 and lid planes 105 of the laptop computer 100.
The RF system 110 includes two parts: a baseband module 120 and RF module 130 respectively connected to the base plane 102 and lid plane 105. The RF module 130 includes active transmit (TX) and receive (RX) antennas. When transmitting signals, the baseband module 120 typically provides the RF module 130 with control, local oscillator (LO), intermediate frequency (IF), and power (DC) signals. The control signal is utilized for functions, such as gain control, RX/TX switching, power level control, sensors, and detectors readouts. Specifically, beam-forming based RF systems require high frequency beam steering operations which are performed under the control of the baseband module 120. The control typically originates at the baseband 120 of the system, and transfers between the baseband module 120 and RF module 130.
The RF module 130 typically performs up-conversion, using a mixer (not shown) on the IF signal(s) to RF signals and then transmits the RF signals through the TX antenna according to the control of the control signals. The power signals are DC voltage signals that power the various components of the RF module 130.
In the receive direction, the RF module 130 receives RF signals at the frequency band of 60 GHz, through the active RX antenna and performs down-conversion, using a mixer, to IF signals using the LO signals, and sends the IF signals to baseband module 120. The operation of the RF module 130 is controlled by the control signal, but certain control information (e.g., feedback signal) is sent back to the baseband module 120. An example for the assembly shown in FIG. 1 can be found in US patent Application Publication 2010/0035561, which is assigned to the common assignee.
Current solutions require least two cables (transmission lines) are needed to transfer the IF, LO, power, and control signals between the baseband and RF modules 120 and 130.
This drawback is critical in millimeter-wave RF systems, e.g., systems that operate in the 60 GHz frequency bands, as the RF module 130 must be located close to the active antennas to perform the functions described above in order to minimize the power loss of the received and transmit signals. Thus, the baseband module 120 is located apart from the RF module 130. Further, because transferring high frequency signals over the cables significantly attenuates the signals, cables that provide low attenuation characteristics are utilized. However, such cables are relativity expensive, thus increasing the bill of material (BoM) of consumer electronics devices.
It would be therefore advantageous to provide a solution for connecting, using a single transmission line, radio frequency modules in an electronic device for use in at least the 60 GHz frequency band.